Topic 2 Nuclear Counting Statistics

1. Topic 2 Nuclear Counting Statistics Random vs Systemic Errors Nuclear Counting Statistics Propagation of Errors Application of Statistical Analysis Statistical Analysis

2. Random vs Systemic Errors Types of measurement errors: Blunders, Systemic and Random Errors Blunders are gross errors such as incorrect instrument setting and wrong injection of radiopharmaceuticals. Systemic errors are results differing consistently from the correct one such as the length measurement by �warped� ruler. Random errors are variations in results from one measurement to another (physical limitation or variation of the quantity) such as the rate of the radiation emission.

3. Accuracy and Precision Measurement results having systemic errors are said to be inaccurate Measurements that are very reproducible (same result for repeated measurements) is said to be precise. It is possible that result is precise but inaccurate and vice versa

4. Nuclear Counting Statistics The Poisson Distribution Standard Deviation The Gaussian Distribution

5. Poisson Distribution Defined only for non-negative integer values The probability of getting a certain result N when the true value is m: P(N;m)=e-mmN/N! Variance, ?2, is defined as such that 68.3% of the measurement results fall within ? ? of the true value m. For Poisson distribution, ?2 = m.